Remodeling of regulation of cell growth by glycogene and its application.

虽然细胞膜组分糖基化的重要性被广泛接受，但其与细胞生长的关系却很少被研究。我们用大鼠β - 1,4 - n -乙酰氨基葡萄糖转移酶III基因（GnT III）转染pc12细胞，重建细胞糖链，并观察其对神经生长因子（NGF）细胞反应的影响。结果表明，在GnT iii转染的pc12细胞中发现了分支结构，这是该基因的产物。然而，没有观察到生长速度或神经突形成的变化。当研究NGF对NGF受体Trk的影响时，没有观察到在对照细胞中发生的酪氨酸磷酸化。此外，信号转导到细胞核所必需的二聚体没有发生。然后，我们通过电穿孔转染b16黑色素瘤（一种常用于转移的细胞系）、NIH3T3和具有EGF受体和GnT III cdna的CHOK1细胞，并选择新霉素耐药细胞。分离到几个高表达gntiii的克隆。通过分割GlcNAc结构修饰EGF受体的糖链，观察到细胞对EGF刺激的反应功能障碍。目前，我们正在研究MAP激酶级联下游的EGF受体信号。

Although the importance of glycosylation of components on the cell membrane is widely accepted, the relationship with cell growth has been only poorly investigated.We remodeled the sugar chains on the cells by transfecting PC 12 cells with rat beta- 1, 4-N- acetlylglucosamyltransferase III gene (GnT III) and effects of them on the cellular responses to the nerve growth factor (NGF) were examined.The results show that branch structure, a product of the gene, was found in GnT III-transfected PC 12 cells.However, no change in the growth rate or neurites formation was observed.When effects of NGF on Trk, a NGF receptor, was investigated, tyrosine phosphotylation, which occurs in control cells, was not observed.Moreover, dimerization essential for signal transduction to nucleus did not occur.Then we transfected B 16 melanoma, a line commonly used for metastasis, NIH3T3, and CHOK1 cells with EGF receptor and GnT III cDNAs by electroporation and selected neomycin-resistant cells.Several clones which highly express GnT III were isolated.The sugar chains of the EGF receptor was modified with bisecting GlcNAc structure and dysfunction of cellular response to EGF stimuli was observed.Currently we are investigating the MAP kinase cascade downstream of the EGF receptor signaling.